湖南省越城岭北部罗汉洞的银杉与长苞铁杉混交林

银杉(Cathaya argyrophylla)是第三纪残遗植物，在当时曾广泛分布于欧亚大陆后在第四纪冰川期遭到浩劫而濒临灭绝1—3]。由于我国南方山地具有得天独厚的地史条件，近年来不断发现幸存的银杉林，迄今已发现广西，湖南、四川及贵州省(区)拥有天然银杉。湖南省于1979年10月在越城岭北部，城步县与新宁县交邻的罗汉洞(沙角洞、乱岩洞)发现1)。位置为北纬26˚33′10″，东经110˚36′32″。先后于1979年10月，1981年4月2)，1981年8月进行了三次调查，本文系在此三次调查的基础上写成。

Cathaya argyrophylla and Tsuga longibracteata Mixed Forest in the Northern part of Yuecheng Ling, Hunan Province

Cathaya argyrophylla is a famous Tertiary relic species and endemic in China. In recent years, it was discovered at the area of the northern part of Yuecheng Ling--the southwest of Hunan (locating in N, 26˚33′ and E. 110˚36′ at an altitude of 950--1050m.)and may be regarded as a news to the province. The mixed forest grows on the top of a cliff which is surrounded by a lot of the higher mountains at alt. 900--1500m. The area is isolated from human disturbance. So it can be survived to date. The compositions and the flora, the layers, the life form, the leaf size class and leaf texture are studied. The result shows that most life form are the chamaephyta and the microphyll with coriaceous texture. According the abundance, dominance and the frequence of the Stands the importance value index are calculated. Basis on the tree analysis of Cathaya the growth curve is given. The related communities in this area are also described.Some problems such as the reasons why Cathaya in this area can be survived, and why the cliff is the common habitat of all Cathaya forests everywhere, and the differences between Cathaya-Tsuga mixed forest in this area and the others are discussed.